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Cosmology Project

Sam Cato

The planets of our Solar System

Mercury has a much faster

orbit than Earth; it takes only

88 days to orbit the sun.

However, it turns extremely

slowly on its axis, so slowly,

in fact, that the sun only rises

and sets twice on Mercury in

a year. Mercury has no

moons.

Venus is a strange, abnormal

planet. It is the only planet in

the Solar System to orbit the

sun clockwise, all the others

orbit anti-clockwise. Also,

Venus is the only planet where the sun rises in the west and sets in the east.

Vaporous, toxic fumes float above Venuss surface, making it impossible for

humans to enter its atmosphere. It too, has no moons.

Earth is the only planet proven to have existing life upon its surface. An

essential of life as we know it is liquid water, and Earth is the only planet to

have this. Earth has a solitary moon, which was probably formed by the

impact of an asteroid.

Mars is nicknamed the red planet because of its reddish surface of rust, or

iron oxide. It has the largest volcano in the entire Solar System, 50 times

larger than any on Earth. It has two moons, which are composed of rock and

ice. It is possible that life once existed on Mars as remnants of bacteria havebeen found.

Jupiter is the largest planet in the Solar System and has over 39 moons! One

of these is called Europa and is one of the most likely planetary bodies to

have life on it. It is one of the four gas planets.

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Saturn is another gas planet. It has over 25 moons and one of these is the

second largest in the Solar System. Its density is so low that that is would

float on water, if there were a large enough ocean. It has rings around it,

which are not solid, but made up of millions of chunks ranging from

microscopic particles to pieces several metres in diameter.

Uranus is also made of gas. Its the only planet to spin on its side. One year

on Uranus is the same as 84 Earth years. It has 21 moons, and Oberon, a

moon is one of the darkest worlds in the Solar System.

Neptune is the last gas planet. It has winds of over 2000km per hour.

Triton, a moon, can get as cold as Pluto (-235 degrees Celsius) It has a

strange orbit, and will soon crash into Neptune or disintegrate.

Pluto has a strange orbit. Mostly, it is the furthest planet from the sun, but itsometimes crosses paths with Neptune. Charon (a moon) is tidally locked

meaning that the same side always faces Pluto.

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Edwin Hubble

Edwin P. Hubble was possibly themost famous astronomer ever. He

was born in Marshfield, Missouri,

U.S.A in 1889. After moving to

Illinois, he was noticed more for his

sporting prowess than his

intellectual ability, but still went on

to study maths and astronomy at

Chicago University. He then went

on to be a high school teacher and

basketball coach, and also served inthe First World War, attaining the

prestigious rank of major.

Hubble is renowned in Science

mainly for the discovery of further

galaxies beyond the Milky Way.

This discovery took place at Mount

Wilson Observatory, where Hubble,

who had been given a position at the

observatory, used the newlycompleted Hooker Telescope to observe the nature of the skies at closer

quarters. He subsequently realised that there were indeed many other

galaxies totally independent from the Milky Way, and this discovery

prompted an enormous alteration in mankinds idea of the Universe. Hubble

also produced a system to identify and classify the galaxies by size,

brightness, shape and distance. He died in 1953, shortly before his work was

nominated for the Nobel Prize. The award is never awarded posthumously,

so Hubble never received this honour that he no doubt deserved. However,

he is remembered vividly by the science community as the most important

and revolutionary telescope (the Hubble Space Telescope) is named after thegreat astronomer.

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Stellar Evolution

This astronomical phraseology

refers to the changes occurring in a

star as it passes through itslifetime. The stars lifespan is said

to be the period of time during

which it emits light and heat.

Changes in the appearance of a star

happen too slowly to be detected, so

astrophysicists created a model of

stellar evolution by observing many

different stars at certain points in

their lifetimes.

The first stage in the formation of astar is the collapse of a stellar

nursery, caused by collision with

another nursery, or by a supernova

explosion. As the nursery collapses,

fragments of gas break away and condense to form extremely hot gas

spheres known as protostars. Depending on the mass and composition of the

protostar, it may morph into a blue supergiant, a sun-like star, or a dwarf

(red or brown). Small protostars do not reach high enough temperatures for

nuclear fusion of hydrogen to occur, and will become brown dwarfs.However, if a high enough temperature is reached, a star may be formed.

After millions of years or more, a stars hydrogen supply may begin to

exhaust. When this happens, the star begins to lose energy rapidly. A variety

of different entities may be formed, including a supernova, a black hole, or a

red giant. Our sun is about halfway through its lifetime, and in about 5

billion years it will become a red giant and engulf the solar system.

A star forming from a stellar nursery